The conventional funnel is inherently unstable and in many instances causes the overflow of liquid that is being poured. This is a problem that occurs quite frequently, for example, with top loading gas tanks for internal combustion engines. Some examples of these would be lawn mowers, leaf blowers, lawn tractors and garden cultivators.
Refueling a hot engine can be very dangerous and can cause the gasoline to ignite and to possibly explode. The directions on most of these engines give a warning about filling a hot engine; however, most users do not want to wait till the engines cools sufficiently and thereby remove the danger but want to continue working without waiting and will refill the engine while it is still hot. This can result in damage to the engine and/or to the operator.
In addition to the unstable characteristics of conventional prior art funnels, the user cannot see when the container (gas tank) is nearly full without stopping the refueling process and removing the funnel to check the fluid level in the tank. This also can lead to gasoline spills as the gasoline overflows from an overfilled gas tank.
Thus, it would be advantageous if a funnel were available that could eliminate most of the problems encountered with refueling a gasoline engine.